Trying to make a water droplet, rotate line into 3d object
USING A SPIN TOOL:


With the pivot point type set to 3D Cursor snap the cursor to the center of a grid (Shift+C) then add a single vertex. In side view create the droplet's profile by extruding the vertex with E or Ctrl+LMB. Go to the top view and press Spin button (located in a Tool Shelf). Play with the steps number.




USING A SCREW MODIFIER


Select the profile and give it a Screw Modifier. Set the steps as you like. This is a better method as it's not destructive for a mesh.